1. Field of the Invention
The present invention is generally directed toward a pinch-type isolation valve comprising an integrated pressurized gas reservoir. The pressurized gas reservoir stores sufficient pressurized gas on board the valve to effect the collapse of an internal sleeve carried by the valve, which closes the valve.
2. Description of the Prior Art
Isolation valves, including pinch-type valves, have been used to control the flow of fluid or particulate material, such as grain, through a conduit, and also to prevent propagation of hazardous conditions, such as fires and explosions, through interconnecting pipes or conveying lines to additional process equipment or operating locations. As many hazardous conditions tend to propagate very quickly, rapid closure of valves is important to the successful isolation of vulnerable process equipment. A number of pinch valve designs have been proposed for various applications.
U.S. Pat. No. 7,246,786 to Schmidt et al. is directed toward a mechanical pinch-type isolation valve for controlling fluid flow in industrial applications. This mechanical valve includes a pair of rotating pinch elements that impinge a rubber spool so as block the flow of material therethrough.
U.S. Pat. No. 5,107,883 to Shaw is directed toward a slow, variable-response pinch valve control system having a network of pinch valves (e.g. for waterlines in a building to reduce/prevent water hammer). Each pinch valve includes a single solenoid operable to rotatably pivot between a first orientation, where compressed gas is directed from a first passageway connected to a source to an inner chamber defined by a sleeve and outer wall of the waterline, and a second orientation, where compressed gas is exhausted from the chamber through a second passageway.
U.S. Pat. No. 5,771,665 to Nelson et al. is directed toward a sand-bagging system and includes a pinch valve that comprises a chamber with laterally-aligned apertures on the sidewall thereof that provide fluid communication between the chamber and a flexible tubular wall and air lines connected to the apertures. A three-way pilot valve permits introduction or evacuation of air via through the lines to compress or expand the wall.
Conventional pinch valves rely upon external resources for providing the motive force, typically compressed air or other fluid, for operation of the valve. If those resources became unavailable, due to plant power failure or damage as a result of a hazardous conditions, the valve would not be operable.